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Show w During the season thirty- six peaks, over 13,000 feet in height, were occupied, and many others of less altitude, which were fixed by triangu-lation processes. At the main points, the angles, repeated, were read from an instrument made by Stackpole, 8" circle, graduated to read by vernier to 10" of arc. At other important points a gradieuta was employed. In addition to the mountain- work, nearly five thousand miles of roads and streams were meandered; the angles being read from a Casella theodolite and the distances measured by an odometer, checked by angles to fixed points, and by sextant observations made by myself for latitude. The area covered is nearly twenty- one thousand square miles. METEOROLOGY AND HYPSOMETRY. At ail camps cistern- barometer readings were taken tri- daily wheu the camps were for an entire day or more, aud at 7 a. m. and 9 p. m. wheu en route. The altitudes of mountain stations were determined by cistern- barometer observations, referred either to our main camps or to the astronomical hourly stations, and by vertical angles from barometric and trigonometric bases. / At topographical stations along roads and streams aneroid readings were taken. The profiles of nineteen passes, eleven over the Atlantic aud Pacific divide, and eight over subordinate ranges, were taken, and the slopes of many beds of streams near their heads determined. GEOLOGY. Prof. J. J. Stevenson, of New York, accompanied the party as geologist, and his report, already submitted, attests the ability and zeal with which he worked in spite of the necessarily limited facilities that could be afforded. NATURAL HISTORY. Dr. J. T. Eothrock and assistant John Wolfe were offered evefy facility and aid in my power in making collections in natural history, and the results, especially in botany, have probably never been equaled by any exploring or surveying expedition to the West. Nearly 12,000 specimens of plants from over 1,100 different species, and large collections in other branches of natural history, were gathered by these gentlemen, and are now being worked up. To these and the other gentlemen of the party, for their efficient aid and exertions during the field- season, I desire to return my thanks. Respectfully submitted. W. L. MARSHALL, First Lieutenant of Engineers. Lieut GEO. M. WHEELER, Corps of Engineers, in charge. The division moving out from Sauta F6 accomplished during the season, with the assistance of the Salt Lake division, the survey of 11,000 square miles in the Territory of New Mexico, and 17,500 in Arizona, in a region possessed of remarkably interesting topographical features. The total area surveyed during the entire season was, approximately, 72,500 square miles. The degree of accuracy of the survey was considerably in advance of that of former years. The connecting station for astronomical signals of the main parties was at the Mormon observ- °+"" v. Salt Lake City, until late in September, when it was transferred |